Enhancing the Strength of Al-B4C Composites to a High Degree by Mg Addition

Abstract

A method of making an Al—B 4 C composite with Mg addition comprising providing a first mixture of B 4 C, Al and Mg powder, producing a powder mixture, adding Mg to the powder mixture, forming pellets, creating a composite, annealing the composite, and forming an Al—Mg—B 4 C composite. An Al—B 4 C composite with Mg addition comprising Al, Mg comprising 4 wt. %, and B 4 C comprising 8 wt. %. An Al—B 4 C composite with Mg addition made from the steps comprising providing a first mixture of B 4 C, Al and Mg powder, producing a powder mixture, adding Mg to the powder mixture, forming pellets, creating a composite, annealing the composite, and forming an Al—Mg—B 4 C composite.

What we claim is: 
     
         1 . A method of making an Al—B 4 C composite with Mg addition, comprising:
 providing a first mixture of B 4 C, Al and Mg powder; 
 mixing the first mixture of B 4 C, Al and Mg powder; 
 producing a powder mixture; 
 adding Mg to the powder mixture; 
 forming pellets from the powder mixture; 
 maintaining the pellets at 615° C. for 30 minutes under Ar atmosphere; 
 deforming the pellets at 600° C. for 30 min; 
 creating a composite; 
 annealing the composite at 630° C. for 4 hours under dynamic Ar atmosphere; and 
 forming an Al—Mg—B 4 C composite. 
 
     
     
         2 . The method of making an Al—B 4 C composite with Mg addition of  claim 1 
 wherein the added Mg comprises 4% of the powder mixture. 
 
     
     
         3 . The method of making an Al—B 4 C composite with Mg addition of  claim 2 
 wherein said step of mixing comprises ball milling with spex 8000M for 30 min; and 
 wherein the hardness of the Al—Mg—B 4 C composite increases by 2 to 5 folds as compared to the hardness of the Al-4% Mg without B 4 C. 
 
     
     
         4 . The method of making an Al—B 4 C composite with Mg addition of  claim 3 
 wherein the powder mixture comprises B 4 C varying from 5, 8, and 12 wt %. 
 
     
     
         5 . The method of making an Al—B 4 C composite with Mg addition of  claim 4 
 wherein the Mg addition improves interfacial adhesion between the matrix and ceramic particles as a result of interfacial boride formation and contributes to the enhancement of strength of the composite. 
 
     
     
         6 . The method of making an Al—B 4 C composite with Mg addition of  claim 5 
 wherein observed strength is greater than 1.0 GPa for the composite comprising 12% B 4 C; 
 wherein the B 4 C particle size ranged from 0.2 to 5 μm with an average size of 0.5 μm; 
 wherein the Al powder particles were in the range of 0.1 to 0.25 μm; and 
 wherein the Vickers hardness, H V , for the 12 wt. % B 4 C composite is in the range of 360 to 460. 
 
     
     
         7 . An Al—B 4 C composite with Mg addition, comprising:
 Al; 
 Mg comprising 4 wt. %; and 
 B 4 C comprising 8 wt. %. 
 
     
     
         8 . The Al—B 4 C composite with Mg addition of  claim 7 
 wherein B 4 C comprises 5 or 12 wt. %; 
 wherein the B 4 C particle size ranged from 0.2 to 5 μm with an average size of 0.5 μm; and 
 wherein the Al powder particles were in the range of 0.1 to 0.25 μm. 
 
     
     
         9 . An Al—B 4 C composite with Mg addition made from the steps comprising:
 providing a first mixture of B 4 C, Al and Mg powder; 
 mixing the first mixture of B 4 C, Al and Mg powder; 
 producing a powder mixture; 
 adding Mg to the powder mixture; 
 forming pellets from the powder mixture; 
 maintaining the pellets at 615° C. for 30 minutes under Ar atmosphere; 
 deforming the pellets at 600° C. for 30 min; 
 creating a composite; 
 annealing the composite at 630° C. for 4 hours under dynamic Ar atmosphere; and 
 forming an Al—Mg—B 4 C composite. 
 
     
     
         10 . The Al—B 4 C composite with Mg addition of  claim 9 
 wherein said step of mixing comprises ball milling with spex 8000M for 30 min; and 
 wherein the powder mixture comprises B 4 C varying from 5, 8, and 12 wt %. 
 
     
     
         11 . The Al—B 4 C composite with Mg addition of  claim 10 
 wherein the Mg addition improves interfacial adhesion between the matrix and ceramic particles as a result of interfacial boride formation and contributes to the enhancement of strength of the composite. 
 
     
     
         12 . The Al—B 4 C composite with Mg addition of  claim 11 
 wherein observed strength is greater than 1.0 GPa for the composite comprising 12% B 4 C; 
 wherein the B 4 C particle size ranged from 0.2 to 5 μm with an average size of 0.5 μm; 
 wherein the Al powder particles were in the range of 0.1 to 0.25 μm; and 
 wherein the Vickers hardness, H V , for the 12 wt. % B 4 C composite is in the range of 360 to 460.